Sanity check on dataimport handler -- what are the implications if status request returns error?

[Shawn Heisey <ap...@elyograg.org>]

What might the implications be if a DIH status request returns an error 
response other than a 404?

A 404 says either the handler or the core probably don't exist.

My guess, and I admit that I haven't read the code closely, is that if 
the handler exists but is so broken that it cannot return a status 
response without encountering an error, that there's no possible way an 
import could have been started.

For those who have spent significant time in the DIH code:  Would that 
be an accurate statement?

In case that's an XY problem, here's the "X":

When making a request with curl, the -f parameter will cause errors 
(including 404) to return an exit code of 22 from curl, and there will 
also be no output from the request.

But when using -f, you can't tell the difference between a 404 and any 
other 4XX error or 5XX response code.  I would like to treat an exit 
code of 22 as a "go" condition for the script rather than a "fail" 
condition.  If the statement I made above is accurate, then this should 
be a safe thing to do -- because if an error response on the status 
request means either a 404 or a problem so severe than an import can't 
possibly be running, I'd be OK doing that.

Thanks,
Shawn